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Bacteria make major evolutionary shift in the lab

  1. Oct 19, 2009 #1

    daniel_i_l

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    I recently came across this article:
    http://www.newscientist.com/article/dn14094-bacteria-make-major-evolutionary-shift-in-the-lab.html
    Has anything on this scale ever been observed before?
    Lenski's freezer must be an immensely valuable source of evolutionary information.
    And one question, why is "lower peak population densities" something E. coli would evolve towards. Wouldn't the more successful ones have a higher population density?
     
    Last edited: Oct 19, 2009
  2. jcsd
  3. Oct 19, 2009 #2
    Wouldn't they have to recreate the phenomenon before they could say the experiment "proves" anything?

    On the other hand, is this different than a bacteria/virus gaining a resistance to a drug? Isn't that a commonly occurring form of evolution along the same lines?
     
  4. Oct 19, 2009 #3

    arildno

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    Not really.

    Most of the immune-resistency comes out of normally "failed" bacteria, i.e, where that structure the anti-biotic targets works IMPROPERLY (thus, the anti-biotic fails to hook onto that defective structure).

    I.e, these mutants would in a non-anti-biotic setting have lower reproduction rates etc than the standard strand, and be quickly swamped/smothered.


    In this case, however, a strictly beneficial trait is seen to emerge, rather than a trait which is onnly beneficial in a much more specialized setting (i.e, the anti-biotic environment)
     
  5. Oct 19, 2009 #4

    ideasrule

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  6. Oct 19, 2009 #5
    I think these experiments are old...
     
  7. Oct 19, 2009 #6

    arildno

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    Well, if they have established that gen 20.000 could give rise to citrate-utilizing gen 32.000, then clearly, the initial observation of citrate-utilization happened well over 10.000 generations ago.
     
  8. Oct 19, 2009 #7

    russ_watters

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    No: evolution does not claim to be a linear process.
     
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